Ann Selzer added that Trump is converting skeptics in the Hawkeye State in a way she has never previously encountered.

“A few months ago, he had the highest unfavorable [rating] of anybody,” Selzer said of Trump on CBS’s “Face the Nation.”

“And people said, ‘Well, he can’t possibly do any better in the horse race because his unfavorable [ratings] are so high,’ ” said Selzer, president of the Selzer & Company polling firm in Des Moines. “Can you ever really turn those around?